The present invention relates to an optical radar apparatus arranged to scan light in a horizontal direction to receive light reflected by an object and returned to the optical radar apparatus so as to detect the distance from the light source to the object and the direction of the object.
Conventionally, an optical radar apparatus of the foregoing type has been proposed to be mounted on a vehicle so as to be used widely as an apparatus for monitoring around the vehicle or an apparatus for controlling the distance from a vehicle ahead. A multiplicity of optical radar apparatuses, each of which is mounted on a vehicle, have been attempted, as disclosed in Japanese Patent Publication 6-137867 to decrease the dead angle by scanning light in the horizontal direction so as to widely detect objects. In general, the optical system for receiving reflected light comprises a lens.
Apparatuses of the above-mentioned type is required to have a small size so as to be disposed in a limited space.
Since a large light receiving aperture is required to maintain the performance of the radar, a limit contradicting the above-mentioned requirement arises.